Where shower facilities are involved, a carrier body is provided that is protected by a sanitary surface material such as tile or acrylic. The carrier body may be installed adjacent to a previously constructed floor or wall structure, and the surface material may extend to cover the adjacent floor or wall structure. The upper surface of the carrier body has a drain opening that connects to a drain for removal of waste water. It is desirable that installation of the carrier body and sanitary surface material, as well as the connection of the drain opening to the drain and the sealing of the carrier body with the adjacent floor or wall structure be carried out quickly and efficiently, and without leaks.
The carrier body during use of the shower supports the weight of the shower user and is therefore a rigid body that provides stable footing for the user and resists cracking or separation of the sanitary surface material.
Some carrier bodies are prefabricated for installation on site. Holzmann et al EP 1 388 317 A2 discloses a prefabricated carrier body formed as a support plate that includes a set of sealing strips attached to and extending along the upper periphery of the support plate. The sealing strips extend outwardly a short distance beyond the periphery of the support plate. The support plate is closely received in an opening formed in the adjacent floor structure and butts up against the adjacent floor structure. As a result, the sealing strips overlap the adjacent floor structure and thereby cover the butt joints. Tiling the adjacent floor surfaces covers the sealing strips and cooperates with the sealing strips to forms a water tight, water-impermeable connection between the carrier body and the adjacent floor structure.
In a similar manner, Illbruck Sanitaertechnik GmbH DE202006012825U1 discloses a prefabricated carrier body formed from rigid foam that includes sealing strips attached to the carrier body. Each sealing strip protrudes from a respective side face of the carrier body. The strips can be glued or otherwise sealingly attached to the adjacent floor or wall structure after installation of the carrier body in the appropriate sized opening.
Prefabricated carrier bodies delivered to installation sites that are carefully prepared to closely receive the carrier body generally present little or no problem in regard to sealing-off the carrier body in relation to its surroundings. But if the carrier body cannot fit, or does not closely fit, into the prepared adjacent floor or wall structure, difficulties can arise in the sealing of the carrier body with the sealing strips, as well as difficulties applying the sanitary surface material—in particular where tiles and limiting dimensions are concerned.
Rather than a prefabricated carrier body, it is also known to provide a premanufactured shower foundation that is directly installed onto the subfloor of a shower stall or alcove and forms the entire shower floor. Providing a prefabricated shower foundation eliminates the need for the services of a skilled craftsman in constructing a shower foundation on site, and a prefabricated shower foundation can be installed in one trip to the job site without the need to wait for adhesive or mortar set up.
A prefabricated shower foundation is disclosed in Young, U.S. Pat. No. 5,845,347. In Young, an injection molded base having a generally flat portion defining the area for the shower floor, an integral, solid vertical curb along one side of the flat portion, and vertical extensions along the other sides of the flat portion is formed from a synthetic resin. The base is intended to rest on the subfloor of the shower stall or alcove, and the curb and vertical extensions contain the water draining from the shower floor during use.
After formation of the base, a waterproof membrane is formed over the base, including the curb and vertical extensions (waterproof as used herein means water-impermeable). The membrane is preferably formed by spraying a liquid synthetic rubber onto the base and allowing the liquid rubber to dry. A continuous sheet of solid waterproof material could be used to form the waterproof membrane but folds or creases in the sheet necessary to conform the sheet to the base prematurely stress the sheet and damages the integrity of the sheet.
After the waterproof membrane is formed, backing material formed as a backer layer is placed over the flat portion of the base and underneath an upper drain portion secured to the base. The backer layer may be made of a plurality of sheets of cement backer boards such as those sold under the DUROCK™ or WONDERBOARD™ trademarks.
The backer layer in Young is not intended to be a waterproof layer or act as an additional waterproof sealing membrane that seals the waterproof membrane applied to the base from water received through the backer layer. As is known to persons of ordinary skill in the relevant shower construction art, cement backer boards are not waterproof, that is, not water impermeable to function as a seal. As explained in Young, the flat portion of the base has its own slope to accommodate the drainage of any water which may seep through the backer layer. The water drains down the base to weep holes in the drain.
Cement backer boards have sufficient flexibility to conform to the slope during installation without cracking. The backing layer after being installed against the base then cooperates with the base to form a rigid carrier body that is capable of providing stable footing for the user and resists cracking or separation of the sanitary surface material applied over the backing layer after the prefabricated shower foundation is installed on site.
Mortar is then applied between the outside edges of the drain portion and the protruding edges of the backer boards to ensure a continuous seal around the drain portion. To complete the prefabricated shower foundation, mortar or like material is molded over the vertical curb to provide additional strength and rigidity.
The prefabricated shower foundation is installed on site in the space designated for the shower stall or alcove. A waterproof plastic lining is attached to the wall studs and over the vertical extensions of the base, and wall panels are placed directly onto the backer layer and are attached to the studs. Sanitary surface material, such as a tile adhered by grout is secured directly to the backer layer and shower walls. Although as pointed out earlier that cement backer boards are not waterproof, the boards do not swell when wet. The structural integrity of the tile, grout, and the backer layer itself is maintained even if water is absorbed through the grout and into the backer layer.
Young discloses a prefabricated base with predetermined dimensions that defines the size of the shower floor, and forming a rigid carrier body sized to those predetermined dimensions.
Another type of prefabricated shower foundation is formed from a thermoplastic plastic sheet that forms a shell having a hollow backside. The shell includes a shower floor portion spaced from the backside, and raised side walls surrounding the floor for containing and directing water flow. The shell alone does not provide the rigidity required for supporting the weight of a user standing on the floor portion of the shell. The shell is filled with a backing material that supports the shell on the subfloor of the shower stall or alcove and cooperates with the shell to form a rigid carrier body capable of stably supporting the user.
Because the upper side of the shell is exposed to view and is itself water impermeable, the shell itself functions as a waterproof layer that covers the backing material.
An example of a prefabricated shell shower foundation is disclosed in Huang et al. US Patent Application Publication US2007/0130685 (“Huang”). As pointed out in Huang, the backing material adds considerable weight to the completed shower foundation. Huang discloses filling the plastic shell with a resinous material and low weight density fillers to reduce the weight of the finished prefabricated shell shower foundation while maintaining suitable structural rigidity.
Both Young and Huang disclose prefabricated shower foundations using a prefabricated plastic base and a backing material that cooperates with the base to form a rigid carrier. In Young, the plastic base supports the backing material while in Huang the backing material supports the plastic base. Young, by placing the backing material over the base, allows for tiled shower floor surfaces which many consumers prefer. Young also provides a redundant waterproof membrane over the plastic base before installing the backing material. In Huang, a redundant waterproof membrane could also be provided by spraying the membrane onto the inside of the plastic shell before adding the backing material.
Kirby US Patent Application Publication 2003/0089059 discloses a construction for a portion of a shower foundation that forms a shower curb. The shower curb is located adjacent to a shower pan and is constructed on site, relying on the presence of a shower liner previously placed to be under an adjacent shower pan construction in which a waterproof membrane formed as a shower liner is provided between the backing material and the sanitary surface material. The backing material is formed by stacking two or three two-by-four dimensional lumber boards in a vertical stack. The bottom surface of the bottom board rests against the subfloor of the shower stall or alcove.
A shower liner is placed over and covers the exposed side surfaces of the boards and the top surface of the top board. A three-sided lattice-like frame is placed over the sheet and the boards. The side of the frame extending along the inner side of the boards extends only partway down from the top surface of the top board. A cementitious material or “mud” is applied over the frame and into the lattice openings to provide a hard surface for laying ceramic tile over the hardened material. The boards support the weight of a user stepping on top of the shower curb's ceramic tile.
The shower liner is positioned below a sloped shower pan that is adjacent to the shower curb. When the shower liner is installed under the shower pan, a sufficient quantity is left over for overlying the boards. Excess shower liner would be trimmed at some point in the construction of the shower curb.
Kirby discloses that the shower curb can be constructed after the remainder of the shower foundation is installed on site and not necessarily constructed as part of a premanufactured shower foundation. The backing material is cut to fit on site, and then assembled after cutting with other components brought to the job site or previously installed in prior construction of the shower foundation.
The shower curb disclosed in Kirby is very similar to the shower curb disclosed in Young. Kirby, like Young, discloses a shower curb element (made of stacked lumber in Kirby, and molded plastic in Young) that rests on the subfloor and a flexible waterproof sheet that overlays and conforms to the shower curb element (although Young prefers a sprayed-on membrane). Kirby, like Young, discloses applying a moldable “mud” or mortar over the sheet overlying the shower curb element, allowing the mud or mortar to harden, and laying tile on the hardened surface. Kirby essentially differs from Young's shower curb only in disclosing a three-sided frame that assists in applying the mud. Kirby's frame could also be adapted for use applying mortar to Young's shower foundation.
Premanufactured carrier bodies with attached peripheral seals and premanufactured shower foundations are not practical for all construction situations. The shower dimensions may not be known, or not known with sufficient accuracy. The shower dimensions may not be compatible with available premanufactured carrier bodies or premanufactured shower foundations.
Thus there is a need for a carrier body assembly that is adaptable on-site for different shower dimensions and not limited to specific, predetermined shower dimensions as are the carrier bodies and shower foundations described above.